Implicit and explicit memory in patients with obsessive-compulsive disorder: an event-related potential study

The implicit and explicit memory in patients with obsessive-compulsive disorder (OCD) was investigated using the event-related potential (ERP). For the assessment of implicit memory, a lexical decision task was administered. Among a total of 320 words and 140 non-words, 200 words were repeated, while the remaining 120 words and the 140 non-words were not repeated. For explicit memory, a continuous recognition task was administered, in which 280 words were repeated and 100 were not repeated. On the recognition task, both the controls and OCD patients showed more positivity to the old words than to the new words during the 200-600 ms period post-stimulus. Both groups showed faster response time to the old words than to the new words. On the lexical decision task, the controls showed the old/new effect during the 200-500 ms period post-stimulus, while the OCD patients did not. However, OCD patient showed faster response time to the old words than to the new words, although OCD patients showed prolonged response times to the old words compared to the controls. These results indicate that OCD patients have preserved explicit and implicit memory. The absence of old/new effect on ERP in OCD patients was discussed in terms of dysfunction of frontostriatal system, which plays an important role in both OCD and implicit memory.     

Working memory dysfunction in schizophrenia patients with obsessive-compulsive symptoms: An fMRI study

BackgroundA substantial proportion of schizophrenia patients also meets DSM-IV criteria for obsessive-compulsive disorder (OCD). Schizophrenia with OCD (“schizo-obsessive”) patients are characterized by distinct clinical characteristics, treatment response and prognosis. Whether schizo-obsessive patients exhibit a distinct pattern of brain activation is yet unknown. To address this question, the present functional magnetic resonance imaging (fMRI) study explicitly compared alterations in brain activation and functional connectivity (FC) underlying a working memory deficit in schizophrenia patients with and without OCD.MethodsfMRI was applied during the N-back working memory (WM) task in three groups: schizo-obsessive (n = 16), schizophrenia (n = 17) and matched healthy volunteers (n = 20). WM-related activation in the right dorsolateral prefrontal cortex (DLPFC) and the right caudate nucleus, brain areas relevant to schizophrenia and OCD, and FC analysis were used for the evaluation.ResultsThe two schizophrenia groups with and without OCD exhibited a similar reduction in activation in the right DLPFC and right caudate, as well as decreased FC compared to the healthy controls. Notably, reduced regional brain activation was not related to severity of schizophrenic or OCD symptoms.ConclusionsSchizo-obsessive patients do not differ from their non-OCD schizophrenia counterparts in brain activation patterns during the N-back WM task. Cognitive paradigms taping alternative neural networks (e.g., orbitofrontal cortex) particularly relevant to OCD, are warranted in the search for potential distinctive brain activation patterns of the schizo-obsessive subgroup.     

强迫症患者工作记忆认知操作功能缺损与完美主义的相关性研究

目的 探讨强迫症患者认知操作功能缺损与完美主义之间的关系。方法 采用方便抽 样法,随机选取 2022 年 1 月— 2023 年 1 月在首都医科大学附属北京朝阳医院临床心理科门诊就诊的 69 例强迫症患者为研究组,同期在北京市朝阳区向社会面招募 74 名健康者为对照组。采用 Frost 多维 完美主义量表中文版（FMPS-C）和工作记忆认知操作任务分别测量两组受试者的完美主义水平以及认 知操作功能,并采用皮尔逊积差相关法分析两者之间的相关性。结果 最终纳入研究组 65 例、对照组 69 名。研究组患者的 FMPS-C 总分、非适应性维度得分高于对照组,适应性维度得分低于对照组,差异 均有统计学意义（均P＜ 0.01）。提示条件为“相反”时,两组受试者对中性、积极、消极 3 种词语的反应 时比较,差异有统计学意义（F=8.943,P＜ 0.01）。两两比较结果显示,研究组患者在 3 种词语刺激下的 反应时均高于对照组,差异均有统计学意义（均P＜ 0.05）。提示条件为“相反”时,研究组消极词语的 反应时长于积极与中性词语反应时（均P＜ 0.05）。两组受试者 3 种词语刺激下的转换消耗值比较,差异 有统计学意义（F=24.378,P＜ 0.001）。两两比较结果显示,研究组患者在中性、积极、消极 3 种词语刺激 下的转换消耗值高于对照组,差异均有统计学意义（均P＜ 0.05）。研究组患者在消极词语刺激下的转换 消耗值高于中性和积极词语刺激的转换消耗值,差异均有统计学意义（均P＜ 0.01）。在中性词语的刺激 条件下,研究组患者的转换消耗值与非适应性维度得分呈正相关（r=0.18,P＜ 0.05）;在消极词语的刺激 条件下,研究组患者的转换消耗值与 FMPS-C 得分、非适应性维度得分呈正相关（r=0.23、0.24;P＜ 0.05）。 结论 强迫症患者存在认知操作功能受损,在处理消极刺激时的受损程度更高,且这种认知操作困难 与非适应性完美主义呈正相关。     

慢性失眠患者数字工作记忆的功能磁共振研究

目的 探讨慢性失眠患者数字工作记忆神经网络连接的改变.方法 采用组块设计方法,分别对40例慢性失眠患者(失眠组)及50例正常睡眠者(对照组)进行数字工作记忆状态下功能磁共振扫描,比较两组受试者在数字工作记忆中反应时间及正确率以及编码、维持、提取阶段脑区激活强度的改变.结果 失眠组与对照组数字工作记忆正确率的比较差异无统计学意义(P＞0.05),失眠组反应时间明显增加,差异有统计学意义(P＜0.01).慢性失眠患者在数字工作记忆编码期激活强度增强的脑区为左侧壳核、豆状核、顶下小叶及右侧尾状核、右枕叶;维持期激活强度增强的脑区为右侧额叶,左侧额叶及额叶内侧面,而左侧额上回激活强度有所下降;提取期激活强度增强的脑区为右额下回及右顶下缘角回,而激活轻度下降的脑区则有左内侧额上回、左岛叶、左后扣带回、左颞上回、左额上回及右颞叶、右后扣带回.结论 慢性失眠患者在数字工作记忆的各阶段,脑区激活强度较健康人有所改变:大脑皮质和皮质下结构广泛受损,即其神经网络连接发生明显改变.     

Neural correlates of working memory dysfunction in first-episode schizophrenia patients: an fMRI multi-center study

Working memory dysfunction is a prominent impairment in patients with schizophrenia. Our aim was to determine cerebral dysfunctions by means of functional magnetic resonance imaging (fMRI) in a large sample of first-episode schizophrenia patients during a working memory task. 75 first-episode schizophrenia patients and 81 control subjects, recruited within a multi-center study, performed 2- and 0-back tasks while brain activation was measured with fMRI. In order to guarantee comparability between data quality from different scanners, we developed and adopted a standardized, fully automated quality assurance of scanner hard- and software as well as a measure for in vivo data quality. After these quality-control measures had been implemented, 48 patients and 57 controls were included in the final analysis. During attention-related processes, even when the performance between patients and controls was comparable, there was a recognizable emergence of cerebral dysfunctions with hypoactivations in the ventrolateral prefrontal cortex (VLPFC), in the superior temporal cortex and in the thalamus. During working memory performance, parietal hypoactivations, especially in the precuneus, were prominent and were accompanied by poorer performance in patients. A hyperfrontality emerged in the ventrolateral prefrontal cortex. Hence, results point to a dysfunctional ventrolateral prefrontal-parietal network during working memory in patients, suggesting impairments in basic functions such as retrieval, storage and maintenance. The brain activation pattern of this large and significant sample of first-episode schizophrenia patients indicates an imbalanced system failing to adjust the amount of brain activity required in the cerebral network involved in attention and working memory.     

Altered verbal working memory process in patients with Alzheimer's disease: an fMRI investigation

Impaired working memory processing is one of the broad range of cognitive deficits in patients with Alzheimer's disease (AD). We aimed to elucidate the differences in brain activities involved in the process of working memory between AD patients and healthy comparison subjects. Twelve patients with AD were recruited along with 12 healthy volunteers as a comparison group. Functional magnetic resonance imaging was employed to assess cortical activities during the performance of a 1-back working memory paradigm using the Korean alphabet as mnemonic content. Subsequently, the difference in neural activities between the 2 groups was analyzed. The AD group performed the tasks with reduced accuracy. Group comparison analysis revealed that the AD group showed decreased brain activity in the left frontal pole (Brodmann area, BA, 10), the left ventrolateral prefrontal cortex (BA47), the left insula (BA13) and the right premotor cortex (BA6) compared to the control group. The AD group showed increased activation in the left precuneus (BA7) compared to the control group. A decreased level of activation in the prefrontal cortex and an increased level of activation in the parietal neural networks from the patient group may document an altered verbal working memory process in the patients with AD.     

Short-term verbal memory deficits in patients with obsessive-compulsive disorder

Recent neuropsychological studies have found deficits in the verbal memory of patients with obsessive-compulsive disorder. Difficulties in using organizational strategies were presumed to be the cause. Preceding studies did not look closely at their ability of feature detection of stimuli. Efficiency in feature detection is crucial to use the attributes or feature of stimuli as a clue in memory tasks. We examined verbal memory deficit and the ability of feature detection in Japanese patients with obsessive-compulsive disorder. We administered Iddon et al.'s verbal strategy task to 16 patients with obsessive-compulsive disorder and 16 healthy controls. The feature of Iddon et al.'s task was to include a phase that showed subjects the semantic structure of the task and timed each subject's analysis of the organization. Patients with obsessive-compulsive disorder were slower to classify stimuli words into semantic categories than were healthy controls. They recalled and recognized significantly fewer words than did healthy controls. In recall tasks, they used less organizational strategy than did healthy controls. Patients with obsessive-compulsive disorder were slower to analyze features of stimuli words than were healthy controls. This slowness possibly contributes to impaired memory performances that patients showed during the encoding process, since the efficient use of organizational strategies in limited time is difficult for them.     

Neocortical system abnormalities in autism: an fMRI study of spatial working memory

OBJECTIVE: To test the hypothesis that deficits in spatial working memory in autism are due to abnormalities in prefrontal circuitry. METHODS: Functional MRI (fMRI) at 3 T was performed in 11 rigorously diagnosed non-mentally retarded autistic and six healthy volunteers while they performed an oculomotor spatial working memory task and a visually guided saccade task. RESULTS: Autistic subjects demonstrated significantly less task-related activation in dorsolateral prefrontal cortex (Brodmann area [BA] 9/46) and posterior cingulate cortex (BA 23) in comparison with healthy subjects during a spatial working memory task. In contrast, activation of autistic individuals was not reduced in other regions comprising the neural circuitry for spatial working memory including the cortical eye fields, anterior cingulate cortex, insula, basal ganglia, thalamus, and lateral cerebellum. Autistic subjects also did not demonstrate reduced activation in any brain regions while performing visually guided saccades. CONCLUSION: Impairments in executive cognitive processes in autism may be subserved by abnormalities in neocortical circuitry as evidenced by decreased activation in prefrontal and posterior cingulate circuitry during a spatial working memory task.     

Altered neural circuit for working memory before and after symptom provocation in patients with obsessive-compulsive disorder

OBJECTIVE: The authors compared the neural circuits recruited for working memory (WM) in obsessive-compulsive disorder (OCD) patients both at a neutral state and at a symptom provoked state. METHOD: Twelve OCD patients, and 12 age-, and sex-matched healthy subjects underwent [(15)O]H(2)O positron emission tomography (PET) scanning, while performing WM task. In the patients, the tasks were performed both in the neutral and in the symptom provoked states. RESULTS: In the OCD patients, the right caudate and the right superior parietal cortex (rSPC) displayed activations for WM at the neutral state, while the right cingulate cortex and rSPC displayed activations for WM at the symptom provoked state. Path analysis revealed that the activity of the caudate and orbitofrontal cortex was altered according to the interaction between WM and symptom provocation. CONCLUSION: The interaction between symptom provocation and WM occurring in the fronto-striatal system may hold the key to the neurobiology of OCD.     

Cognitive dysfunctions in patients with obsessive-compulsive disorder compared to the patients with schizophrenia patients: relation to overvalued ideas

OBJECTIVE: The clinical overlaps between schizophrenia and obsessive-compulsive disorder (OCD) seem to be related to thought disorders involving obsessions, overvalued ideas, and delusions. Overvalued ideas are beliefs falling in between obsessions and delusions and are stronger than obsessions but weaker than delusions. The goal of the present study was to compare patients with OCD to those with schizophrenia in terms of cognitive functions and to relate cognition and overvalued ideas in OCD. METHODS: Twenty three patients with OCD (free of depression), 24 patients with schizophrenia, and 22 healthy subjects matched to patients in age, gender, education, and hand dominance were included in the study. All subjects were administered neurocognitive tests assessing verbal learning-memory, executive functions, verbal fluency, attention and verbal working memory. RESULTS: Patients with schizophrenia showed worse performance on cognitive tests than the OCD and control groups. The severity of overvalued ideas was significantly correlated to cognitive functions in the OCD group. There were no significant differences in cognitive functions between schizophrenia group and the OCD patients who had higher scores on the Overvalued Ideas Scale (OVIS). CONCLUSION: Overvalued ideas in OCD may be related to cognitive dysfunctions in OCD and this subtype of OCD may have similar characteristics to schizophrenia in terms of cognition.     

Shared executive dysfunctions in unaffected relatives of patients with autism and obsessive-compulsive disorder.

BACKGROUND: Executive dysfunctions have been studied as a potential endophenotype associated with the genetic basis of autism. Given that recent findings from clinical and molecular genetic studies suggest that autism and obsessive-compulsive disorder (OCD) could share a common pattern of heritability, we assessed executive functions as a possible common cognitive endophenotype in unaffected family members of individuals with either autism or OCD. METHODS: Five tests assessing executive functions (Tower of London, verbal fluency, design fluency, trail making and association fluency) were proposed to 58 unaffected first-degree relatives (parents and siblings) of probands with autism and 64 unaffected first-degree relatives of OCD patients. Results were compared with those of 47 healthy controls matched for age, sex, and level of education. RESULTS: In the Tower of London test, both groups of unaffected relatives showed significantly lower scores and longer response times compared with controls. No differences were observed between autism and OCD relatives and healthy controls in the four other tasks (verbal fluency, design fluency, trail making test and association fluency). CONCLUSIONS: Our findings show the existence of executive dysfunction in the unaffected first-degree relatives of probands with OCD, similar to those observed in the relatives of patients with autism. These results support and extend previous cognitive studies on probands indicating executive dysfunctions in autism and OCD. Planning and working memory processes could thus represent a common cognitive endophenotype in autism and OCD that could help in the identification of genes conferring vulnerability to these disorders.     

Nonverbal memory dysfunction in obsessive-compulsive disorder patients with checking compulsions

Obsessive-compulsive disorder (OCD) is a clinically heterogeneous disorder; nonetheless, most of the previous neuropsychological studies for assessing the involvement of memory dysfunction grouped together patients with different symptoms, thereby potentially accounting for the inconsistencies of results. The goals of this study were to compare the memory dysfunction of two main subtypes of OCD and to identify the type of memory dysfunction that is associated with the checking symptoms in OCD patients. The sample population comprised the cleaning-type OCD group (N=23), checking-type OCD group (N=24), and a control group of healthy volunteers (N=20). All the OCD patients were selected from the outpatient clinic. All the subjects underwent the Rey-Osterreith Complex Figure Test (RCFT) for the assessment of nonverbal memory function, the Hopkins Verbal Learning Test (HVLT) for verbal memory function, the Wechsler Adult Intelligence Scale-Revised (WAIS-R), and the Wisconsin Card Sorting Test (WCST). The immediate and delayed memory scores of RCFT were significantly lower in the checking-type OCD group; there were no significant differences in HVLT scores amongst the three groups. Our results indicate that the checking-type compulsion of OCD patients is associated with nonverbal memory deficits and not with verbal memory deficits.     

Bupropion for patients with obsessive-compulsive disorder: an open-label, fixed-dose study

OBJECTIVE: In the present study, we examined the efficacy of bupropion for patients with obsessive-compulsive disorder (OCD). METHOD: Twelve patients with OCD according to DSM-IV criteria were included in an open trial with bupropion, maximum dosage 300 mg per day, during 8 weeks. The primary efficacy parameter was the Yale-Brown Obsessive Compulsive Scale (YBOCS). A responder was defined by a reduction in score on the YBOCS of > or = 25%. Data were collected from February 2003 to July 2003. RESULTS: An intent-to-treat analysis using the last observation carried forward demonstrated that bupropion had no mean effect on OCD symptoms (mean YBOCS decrease was 1.1 +/- 9.6). Four patients improved, with a mean decrease on the YBOCS of 31%, and 2 of them met responder rate criteria. Eight patients experienced an exacerbation of OCD symptoms, with a mean increase on the YBOCS of 21%. CONCLUSION: Bupropion is not an effective treatment for OCD, but the bimodal distribution of the effect supports the notion that dopamine might be involved in the pathophysiology of OCD.     

Honig's model of working memory and brain activation: an fMRI study.

The present study investigated changes in neuronal activation with fMRI related to Honig's model of working memory, which is much less studied compared with other working memory models. In contrast to other studies which have applied recognition procedures, the primary aim with the present study was to examine brain activation when subjects had to continuously recall and forget items held in working memory. The results showed that the mid-ventrolateral frontal cortex was particularly activated in the left hemisphere, whereas the mid-dorsolateral frontal cortex was particularly activated in the right hemisphere during execution of the working memory task. The findings are discussed in relation to process- and domain-specific accounts of working memory.     

Clinical correlates of word recognition memory in obsessive-compulsive disorder: an event-related potential study

Memory disturbances found in obsessive-compulsive disorder (OCD) may partially be related to dysfunction of cortico-subcortical circuits. However, it is still unknown how OCD symptomatology is related to memory processing. To explore this question, event-related potentials (ERPs) were recorded in a continuous word-recognition paradigm in OCD patients with either severe or moderate scores on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) (group S and group M, n=8 each) and in normal healthy controls (n=16). Typically ERPs to repeated items are characterized by more positive waveforms beginning approximately 250 ms post-stimulus. This "old/new effect" has been shown to be relevant for memory processing. The early old/new effect (ca. 300-500 ms) with a frontal distribution is proposed to be a neural correlate of familiarity-based recognition. The late old/new effect (post-500 ms) is assumed to reflect conscious memory retrieval processes. The OCD group S showed a normal early old/new effect and a reduced late old/new effect compared with group M and the control group, but no difference was found between group M and the control group. Source analyses for the late old/new effect showed statistically reduced cerebral activation in the anterior cingulate for OCD group S in contrast to the control group. Additionally, the early old/new effect in OCD group S was negatively correlated with the Y-BOCS total scores, and the late old/new effect was negatively correlated with obsession sub-scores. The severely, not moderately, ill OCD patients showed an impaired conscious recollection of the word-to-be-remembered, which suggested an impairment of working memory capacity in these patients due to a dysfunction in the frontal and cingulate cortex.     

"What"-Then-Where" in visual working memory: an event-related fMRI study

Behavioral studies indicate that spatial and object working memory are computed by dissociable subsystems. We investigated the neural bases of this dissociation with a whole-brain fMRI design and analysis technique that permitted direct assessment of delay-period activity, uncontaminated by other components of the trial. The task employed a "what"-then-"where" design, with an object and a spatial delay period incorporated in each trial; within-trial order of delay conditions was balanced across each scan. Our experiment failed to find evidence, at the single-subject level and at the group level, for anatomical segregation of spatial and object working memory function in the frontal cortex. Delay-period activity in the caudate nucleus revealed a sensitivity to position in the trial in the spatial, but not the object, condition. In posterior regions, spatial delay-period activity was associated with preferential recruitment of extrastriate areas falling within Brodmann's area 19 and, less reliably, the superior parietal lobule. Object-specific delay-period activity was found predominantly in ventral regions of the posterior cortex and demonstrated more topographic variability across subjects than did spatial working memory activity.     

Predictors of treatment response to fluvoxamine in obsessive-compulsive disorder: An fMRI study

Recent neuroimaging studies suggest that the pathophysiology of obsessive-compulsive disorder (OCD) may involve more widely distributed large-scale brain systems, including the parietal, occipital, and cerebellar areas, rather than the conventional orbitofronto-striatal model. We hypothesized that not only orbitofrontal cortex and caudate nucleus activities but also posterior brain regions might be associated with subsequent treatment response to serotonin reuptake inhibitors in OCD. The participants were 17 patients with OCD. Each patient was required to undergo fluvoxamine pharmacotherapy for 12 weeks. Before treatment, fMRI images of the subjects were obtained in the context of a symptom-provocation paradigm. The percentage changes in total Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) scores, from pre- to post-treatment, served as the index of treatment response. Statistical Parametric Mapping was used to identify brain loci where pre-treatment brain activation significantly correlated with the subsequent treatment response. Fifteen of 17 patients completed the 12-week treatment. During the symptom provocation task, patients showed brain activation in the left superior temporal gyrus (STG), left precuneus, left frontal cortices, right cerebellum, and right frontal cortices. We found that pre-treatment activation in the right cerebellum (Z-score = 5.10, x,y,z=22,-84,-18) and the left STG (Z-score = 4.95, x,y,z=-62,-22,0) was positively correlated with the improvement in the Y-BOCS score. Our results suggest that pre-treatment activation in the right cerebellum and in the left STG predict subsequent reduction in OCD symptom severity. There is every possibility that fMRI can be used as a tool to predict treatment response.     

Disorder-specific dysfunctions in patients with attention-deficit/hyperactivity disorder compared to patients with obsessive-compulsive disorder during interference inhibition and attention allocation

Background: Abnormalities in inhibitory control and underlying fronto‐striatal networks is common to both attention deficit hyperactivity disorder (ADHD) and obsessive‐compulsive‐disorder (OCD). The aim of this study was to investigate disorder‐specific abnormalities in neural networks mediating interference inhibition and selective attention. Method: Event‐related functional magnetic resonance imaging (fMRI) was used to compare brain activation of boys with ADHD (18), with OCD (10), and healthy boys during (20) during a Simon task that measures interference inhibition and controls for and therefore comeasures attention allocation. Results: During interference inhibition, both patient groups shared mesial frontal dysfunction compared to controls. Disorder‐specific dysfunctions were observed in OCD patients in dorsolateral prefrontal cortex during the oddball condition and in ADHD patients in inferior parietal lobe during interference inhibition and in caudate and posterior cingulate during the simpler oddball condition. The decreased activation in caudate and cingulate in ADHD was furthermore negatively correlated with ADHD symptoms and positively with OCD behavioral traits. Conclusions: The study shows that ADHD and OCD patients have shared but also disorder‐specific brain dysfunctions during interference inhibition and attention allocation. Both disorders shared dysfunction in mesial frontal cortex. Disorder‐specific dysfunctions, however, were observed in dorsolateral prefrontal cortex in OCD patients and in caudate, cingulate, and parietal brain regions in ADHD patients. The disorder‐specific dissociation of striato‐cingulate activation that was increased in OCD compared to ADHD patients, was furthermore inversely related to the symptomatology of the two disorders, and may potentially reflect differential dopamine modulation of striatal brain regions. Hum Brain Mapp, 2011. © 2010 Wiley‐Liss, Inc.